Alarm system



April 14, 1931.

ALARM R. O. HARRELL SYSTEM dmmsfiunoy 7 CENTRAL 514110;:

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L INVENTOR 1 7 Rzczmzw QI ZRRE L BY Md ATTORNEY Patented Apr. 14, 1931 UNITED STATES PATENT OFFICE RICHARD O. HARRELL, OF SOUTH BOSTON, VIRGINIA LARM SYSTEM Original application filed April 2, 1928, Serial No. 266,775. Divided and this application filed February 2, 1929. Serial No. 337,096.

This invention relates to improvements in alarm systems of the electrical nature, and

it consists of the constructions, combinations and arrangements herein described and claimed.

An'object of the invention is to provide an electrical system by which either a fire or burglar alarm originating at a subscribcrs station may be given at a central station, the

particular feature of the system being the persistence of the alarm at the central station regardless of the fact that the condition which set off either type of alarm may'have been remedied. i Another object of the invention is to combine the alarm system with a telephone set, thus providing a composite alarm and telephone system, one of the outstanding advantages being the ease with which a highly effective alarm system can be installed to the end that the benefits of constant supervision and promptattention to duty, which are characteristics of the modern telephone system, will instantly inure to the user.

A further object of the invention is to reduce the requirements for a perfectly protected premises to the wiring of the various doors, windows and other points to be guarded, concludingby merely hooking up with the available type of telephone set which is presumed to have been equipped with a certain electro-magnetically operated switch which is the subject matter of a co-pending application filed April 2, 1928, Serial No. 266,7 7 5 of which the instant application is a division.

Other objects and advantages appear in the following specification, reference being had to the accompanying drawing in which The View is a diagram of the alarm system, showing how it is combined with a telephone system.

As has been indicated already in a general way, it is the purpose of the invention to provide an electrical system bywhich either a fire or a burglary in a subscribers station or other protected premises, will be made evident at a central station at which an operator is supposed to been duty. Many such systems have been devised and put into practice, but it seems that those which have survived possess initial difficulties of introduction, installation and the like so that the benefits of a simple yet effective system are yet to be realized.

Instances have been known to occur in which the most elaborately protected premises have become the successful object of burglarously inclined persons. A little deftness of the fingers and some knowledge of electrical circuits seem to constitute the sole requirements of a person with temerity enough to enter a house that is known to be wired for burglar alarms. Other instances have been known wherein the alarm system has functioned without provocation thus arousing the night-watch to unwarranted and perhaps unwonted activity.

All of the effects and advantages of an eiiicient alarm system have been derived from the application of the simplest principles, the outstanding feature being the persistence of the alarm at the central station until a certain auxiliary switch has been reset at the premises from which the alarm originated, regardless of the fact that the condition which started the alarm has been remedied. For example: The breaking out of a fire can give cause for alarm both at the subscribers and central stations. The fire may be extinguished, but unless the auxiliary switch is reset the alarm will persist.

So is this true in case of a burglary. A burglar may enter a door or window, and if he comes into contact with the electrical apparatus it will be instrumental in giving an alarm at the central station. This will be done without arousing the suspicions of the burglar. Steps can be taken to apprehend the latter. Regardless of the fact that the burglar may be apprehended, the alarm condition will prevail untilthe auxiliary switch is reset.

Attention is directed to the drawing. The structure illustrated beneath the line 1 is to be regarded as being installed in a protected premises which is also herein known as the subscribers station. The premises may comprise a dwelling, factory, store or the like.

The alarm system is intended to be operated in conjunction with the telephone system, the central station 2 of which is connected with the subscribers station by means of line wires 3 and. 4. Another subscribers station 5,

marked Outside station, is connected with the central station byline wires 6 and 7. An

owner at home in his residence may have the central operator in station 2 make connectlon. with his protected premises 1 and thus satisfy himself as to conditions there.

The telephone set is indicated 8. This'may' comprise any known commercial desk or wall set. The lnvention is not concerned with the wiring of the set other than to the. following a extent: The receiver 9 is-adapted to hang on ahook 10 which is pivoted at 11 and is" telephone set 8. As stated before, this is the 1; subject ot-aco-pendi-ng application. Abrief description of it followsz -The auxiliary switch isgenerally indicated 17. It has contactors 18, 19-and 20 that are to beregarded as duplicate'sof thecontactors 1'2, 13 and 14, respective connections being made by wires 21, 22 and-23. These wires connect the main switch in parallel with the auxiliary switch. The closure otthe main switch M, as by removing the receiver 9 from the hook 10, would put the telephone set in operationwithout affecting the auxiliary switch 17. y y

The j closure of the auxiliary switch 17 would place the telephone "set in communication with the centralstation 2 without affecting the main switch M1 It'is thus not'essene tial' that the receiver 9 be removedfrom the hookin order to establish communication be? tween the subscribers station land the central station 2. Th1s 1s-animportant consideration-in the operation of the alarm system.

An elect'ro-magnet 24 is, included in. the auxiliary switch. It has a pivoted armature 26. ,l/Vhen the armature is in the released position shown it rests on the shoulder 28 of a. resettinglever 29. That lever is pivoted at 30. :T he'end opposite to the pivot extends heyond thjeshoulder 28 to form a stop 38. The lever is movable by a resetting rod 31 which carries a button 32 which is pressed upon to-perform a resetting operation. i

A hearing 33si1pports the rod. A spring 34 presses against one end of the bearing and againstawasher 35 on the rodthus tending to push the rod out. Therod carriesa separater 36wh1clr1s engageable with the con- ,tac'tor 18. In this respect the resetting rod may act as does the telephone hook 10. Pressure on the button 32 will cause. the separator 36 toseparate the contactors of the auxiliary switch 17. That is -the condition while the .soundwhen afire breaks out. No audible alarnrwill occur in case ota burglary, but the central operator will perceive an alarm condition and will take steps toward the apprehension of the intruder. I v

A local battery 42 supplies current for the operation of the audible devices and the auxiliary switch. A wire 43 connects the positive pole of the battery with one side of the electro-magnet 24, the other side having a wire 44 joined with a wire 45, one end of whichis connected with a terminal 46 of a heat controlled. switch 47, the other end being-connected with one of the contactors 48 ot a window swltch. The other contactor of that switch is designated 41. The contacts are separated by a pin 49when the window 50 is down. I

The other terminal 51 or the switch 47 is connected'by means of a wire 52 with a wire 58 that is common to both devices 39 and 40.. A second wire 54 is also common with a negative return 'wire 55th-at has-com nection with the negative pole of the battery andywithone terminal 56 ofa lockswitch5i.

The other terminal58 of that switch-has-conncction through a wire 59 with a'wire 66 that common to the contacto'r 41 and a contactor 59 ot'madoo'r switch 60.. The other-contact 61 of that switchis. connected with the wire 45 by a wire 62. A pin 63 on the door 64 separates said contacts when thedoor-is closed. 6

A fusibleeleinent 65 keeps the .heatcontrolled switch '47 open while intact.v This element is anchored at 66 and is connected with the plunger 67. In practice the plunger hasa spring which tends to move it'toward the terminal 46. The lock switch 57 is subject to closure when the bolt'69 ofthedoor lock 70 is projected as when the door 7' 1 is locked. 7 p

The operation is readily understood. The ordinary use of the telephone set 8 is. as follows: As long as the receiver 9' remains in place on the hook 10 the internal talking circuits will be open. These talking circuits have nothing to do with the inventiom'hence nected in parallel with the 'main' switch M,

at l

, will hear the bell 39 ring.

is, like the main switch, normally open. The position is shown in the drawing.

The action in case of a fire is as follows The heat will fuse the element 65 permitting the movement of the plunger 67 into engagement with the terminal 46. This will cause the operation of the auxiliary switch 17 and the ringing of the inside bell 39 and outside gong 40. For these purposes current flows as follows:From the positive pole of bat tery 42 over wire 43, electro-magnet 24, wires 44 and 45 to the terminal 46, past plunger 67 to terminal 51, over wires 52 and 53 to the bells and over wires 54 and 55 to the negative pole of the battery.

As a result of this the energized magnet 24 attracts the armature 26. The resetting lever 29 will be released so that the spring 34 projects the resetting rod 31 to the right and the separator 36 departs from its position against the contactor 18 of the auxiliary switch 17. The contactors of that switch are thus permitted to engage. The effect is the same as though the telephone receiver 9 had been lifted from the hook 10,

but it must be borne in mind that this has not been done and that the main switch M has not been closed. The closure of the auxiliary switch 17 has the same effect.

In the centralstation 2 the central operator will receive the indication of a call- Making her'connection with the subscribers station 1 she will receive no answer. But she know that there is a fire and will call the fire department. The fire alarm system when once set in operation cannot be stopped until, first, a new fusible element is inserted in the switch 47 and, second, the switch 17 is reset by pushing in on the button 32. The insertion of the new fusible element would open the bell circuit but it would not restore the auxiliary switch 17 That would be necessary to assure the central operator that the alarm 3 condition has been relieved, and the resetting of the switch by means of the button 32 is necessary to achieve that result.

The action in case of a burglary is as follows:Upon closing the premises for the night the last person out is supposed to see to the closing and locking of all doors and windows. The door 71 is regarded as the front door; the bolt 69 of the lock 70 must be thrown in order to close the lock switch 57 which constitutes the control for the burglar alarm. The alarm is set in readiness for operation by the final closing of the premises and locking of the front door at 69. Failure to lockthe front door would leave the premises unprotected against a burglary.

Assume the window 50 to be opened. The contactors 41 and 48 of the window switch would be permitted to engage and immediately close a circuit through the magnet 24 so that the armature 26 would be attracted. An

She will thus opening of the window 50 and an immediate closing thereof would have the same elfect. The immediate opening of the window switch would not reset the auxiliary switch 17 which was closed by the attraction of the armature 26.

The operator in the central station 2 will now receive notice of a call from station 1. The telephone set 8 is placed in communication with the central station, the auxiliary switch 17 placing said set in such con'nnunication in shunt around the main switch M. Inquiring the number wanted and receiving no response from station 1 the central operator will be put on notice that an alarm condition exists there. She will assume that an unauthorized entrance is being effected and will thercfore notify the proper authority.

An opening of the door 64, or an opening an immediate closing of that door will have the identical effect on the auxiliary switch 17. "he facts of the telephone receiver 9 being either on or oil' the hook 10 make no difference in the operation of the alarm system. A person may be using the telephone as in conversation and the fire alarm will go off, in case of a fire, before he has replaced the receiver.

Suppose a burglary to be in process in the premises 1 and the central operator to be remiss in .her vigilance, and suppose further, that the owner residing at station 5 coincidentally calls up his premises 1 in order to assure himself that conditions are safe. If all of the various contacts and door switches are properly open and closed, as the case may be, the usual bell of the telephone set 8 could be rung by the central operator. But if the window switch or door switch 60 were closed, the resulting closure of the auxiliary switch 17 would prevent the ringing of the telephone bell as is usual, but the premises 1 would be placed in communication with the central station 2 and so with the outside station 5.

The owner making the call would listen, and if the burglar failed in his precautions toward any noises in his nefarious operations he would immediately reveal his presence and so admonish the listener to call the police. The window and door switches may be regarded as somewhat symbolical. Other circuit closing devices may be employed in connection therewith. For instance, the window opening may be guarded by a network of cords, the breaking of which would cause the engagement of certain wires for a circuit closure through the magnet 24.

Other applications of the alarm system will suggest themselves in practice. It is not within the province of this disclosure to state all of the ways in which the invention may be used, and while the improved alarm system is that of a generally preferred form, ob-

viou'sly modifications may he made Without departingfrom the spirit ofthe invention 0 the scope of the claims. 7

1. A silent burglar alarm comprising a central station, a subscribers station having a window and a door With a lock, a telephone set in the subscribers station having a rn ain switch and bell in circuit With the central station, a local circuit in parallel With said set, a switchin the door lock partially closing the local circuit vupon locking the door, a

switch at the Window conipletingthe closure of thelocal circuit upon opening the Window,

and an auxiliary switch in the local circuit operated upon said circuit co1npletion-cut-' tingout the. main switch to prevent ringing of the hell and placing the subscribers station in listening communication With the central station. a

2. A silent burglar alarm comprising a pair of subscribers stations, a telephone set including a bell and a main switch in each subscribers station, an intermediate central station in electrical connection \Vltll said stations, a local protector circuit in one of the suloscriloefis stations, and means operated upon closure of the protector circuit to cut out the main switch andbell of the respective set and complete a circuit to the central station to preVent'ringi-n-g of thehell but enable listening from the second suhscribers station upon the making of a call from said second station through thegcentral station to the V firststation. V.

RICHARD O. HARRELL. 7 

